Strange and unique caves in Phong Nha

A series of caves – strange as vertical cave skylights – has been discovered in Phong Nha – Ke Bang, Quang Binh, Vietnam. They are unique in the world, said Mr Howard Limbert.

Unlike the other popular type caves in the World, the caves have been discovered like vertical large holes, hundreds of meters deep. In order to hanging down to the bottom, only real experts can do, no places to cling on the wall of caves.